These words describe the shape of a disc on a scan. A bulge is a broad, shallow extension of the disc's edge. Protrusion and extrusion are two shapes of herniation, where disc material is displaced at one spot. The word describes the shape of what the scan shows. It does not, on its own, say how severe your symptoms will be or whether surgery is needed.
Assessing and treating lower back pain in Burlington, Ontario.
When to see a doctor firstBroader Low Back Pain GuideRadiology societies in North America agreed on standard definitions for these terms. Reports do not always follow them exactly, so the wording can vary between radiologists.
| On the report | What it means |
|---|---|
| Disc bulge | The edge of the disc extends past the bone around a wide part of its rim. In the standard terms a bulge is not a herniation. |
| Herniation | Disc material is displaced beyond the normal edge of the disc at one spot. Protrusion, extrusion and sequestration are types of herniation. |
| Protrusion | A herniation at one spot whose base is wider than the displaced part, measured in the same scan view. |
| Extrusion | A herniation whose displaced part is wider than its base in at least one scan view, or that has separated from the disc. |
| Sequestration or free fragment | An extrusion in which the displaced piece has completely separated from the disc it came from. |
| Central, paracentral, foraminal | Where the displaced material sits: in the middle of the canal, just off to one side, or in the side opening where a nerve root exits. |
| Broad-based or focal | How wide the displaced area is. |
"Slipped disc" is an everyday term for a herniation. Discs do not slip out of place; the word describes material from inside the disc moving outward.
New difficulty passing urine or controlling your bladder or bowels, or numbness around the groin, genitals or inner thighs
Go to emergency now. These can be signs of pressure on the nerves at the base of the spine (cauda equina syndrome).
Weakness in a leg or foot that is new or getting worse, or a foot that drags
Seek same-day medical assessment.
Leg pain, numbness or weakness in both legs at once
Seek same-day medical assessment.
Back pain with fever, chills or feeling generally unwell
Seek same-day medical assessment to rule out infection.
A review of 33 studies, covering 3,110 people with no back pain, estimated that disc bulges show on scans in 30% of 20-year-olds and 84% of 80-year-olds, and disc protrusions in 29% of 20-year-olds and 43% of 80-year-olds.
So a bulge or a protrusion on a report does not, on its own, explain back or leg pain. It matters when it fits your symptoms and the exam.
They can. A review of studies of people treated without surgery, who had more than one scan, estimated that the displaced material shrank in 96% of sequestrations, 70% of extrusions, 41% of protrusions and 13% of bulges. It disappeared completely in 43% of sequestrations and 15% of extrusions.
In that review, sequestrations and extrusions were the types most likely to shrink. A word that sounds worse on the report does not mean a worse outlook, and symptoms can improve whether or not the picture changes.
I start with where the pain travels and which movements and positions change it, then test strength, reflexes and sensation in the legs. That helps assess whether a nerve root is involved and whether the findings fit the level and side named on the report.
Most plans combine staying active, positions and movements that ease the leg symptoms, and graded exercise as things settle. I cannot order imaging. When a scan would change the plan, I flag it to your family doctor or specialist and refer you. More on the disc herniation page.
Not in the standard terms. A bulge is a broad extension of the disc's edge. A herniation is disc material displaced at one spot, and protrusion and extrusion are two of its shapes. In everyday use the words are often mixed.
Not on the word alone. The two terms describe the shape of the herniation, not its size or how it will behave. In a review of people treated without surgery, extrusions shrank more often than protrusions (70% compared with 41%). What matters most is whether a nerve is affected and how your symptoms are changing.
Bulges were the least likely to change on repeat scans in that review (13%). Many bulges are also present in people with no pain, so the aim of treatment is your symptoms and function, not the picture.
For most people, yes, and staying active is part of usual care. The starting point depends on the exam, and I adjust it from how your back and leg respond. New or worsening leg weakness needs urgent medical assessment. New difficulty passing urine, loss of bladder or bowel control, or numbness around the genitals or anus needs emergency assessment.
Most people with a disc herniation are managed without surgery. A surgical opinion may be considered when leg pain keeps causing substantial pain or limiting what you can do despite non-surgical care, and the scan fits the symptoms. New or worsening leg weakness needs urgent medical assessment. New difficulty passing urine, loss of bladder or bowel control, or numbness around the genitals or anus needs emergency assessment.
The main sources behind this guide. Other studies are named in the text where they are used.
2014 Fardon DF, Williams AL, Dohring EJ, et al. The Spine Journal
The consensus recommendations of three North American spine and radiology societies on the standard terms for normal and abnormal lumbar discs, including bulge, protrusion, extrusion and sequestration.
2015 Brinjikji W, Luetmer PH, Comstock B, et al. American Journal of Neuroradiology
In 33 studies of 3,110 people without symptoms, disc bulge was present in 30% of 20-year-olds and 84% of 80-year-olds, and disc protrusion in 29% and 43%.
2015 Chiu CC, Chuang TY, Chang KH, et al. Clinical Rehabilitation
In studies of patients treated conservatively with at least two scans, the rate of spontaneous regression was 96% for sequestration, 70% for extrusion, 41% for protrusion and 13% for bulging, with complete resolution in 43% of sequestrated and 15% of extruded discs.
Fuller pages for the conditions these report words most often relate to.
I see patients for lower back pain at Endorphins Health & Wellness Centre in Burlington. The clinic serves people coming in from Burlington, Waterdown, Oakville, Hamilton, Flamborough, and Carlisle, with free parking on site and a ground-floor entrance.
Burlington hours
